1. Field of the Invention
The present general inventive concept relates to an ink composition including an azo-based colorant and an ink set using the same, and more particularly, to an ink composition which uses a lithium salt and a derivative including hydroxynaphthalene of a chromophore as colorants, and includes etriol and an acetylene glycol-based compound to improve a solubility and a thermal stability, and an ink set using the same.
2. Description of the Related Art
Generally, a pigment-type ink for inkjet printers needs to have stable properties during long-term storage, a solubility of dyestuffs in ink for inkjet printers needs to be high enough not to block inlets of nozzles, and printed images need to have a high optical density. In addition, ink should not block the nozzles due to decomposition and kogation during long-term storage.
Recently, thermal head inkjet printers and piezoelectric head inkjet printers have been widely used, and thus ink of inkjet printers need to have properties suitable for both types of inkjet printers.
Colorants, including a lithium salt and a derivative including hydroxynaphthalene of a chromophore, have been widely used in inkjet ink, printing ink, paints, textile printing, paper manufacture, cosmetic manufacture, the ceramic industry, and the like.
Colorants, including anionic dyestuffs and lithium salts, have been already disclosed. For example, according to U.S. Pat. No. 6,395,885, when the anionic dyestuffs and lithium salts are used together, a solubility and a lighffastness can be improved.
However, the improved solubility is not sufficient to prevent blocking nozzles in array head printers, and a reaction of colorants and an occurrence of kogation on a surface of a heater.